What is Haab's Striae in Glaucoma?
Haab's striae are distinctive curvilinear breaks in Descemet's membrane, serving as a key indicator of corneal stretching in primary congenital glaucoma.
Haab's striae are curvilinear breaks in Descemet's membrane, which is the elastic, innermost layer of the cornea. These unique corneal findings are a direct consequence of the acute stretching of the cornea, occurring specifically in cases of primary congenital glaucoma.
Key Characteristics and Clinical Significance
The presence and orientation of Haab's striae are crucial for diagnosis in pediatric ophthalmology:
- Nature of the Break: They are actual tears within Descemet's membrane, a critical component of the corneal structure.
- Underlying Cause: Haab's striae develop due to the sustained elevation of intraocular pressure in primary congenital glaucoma. The young, elastic cornea in infants stretches under this pressure, leading to these characteristic breaks.
- Typical Orientation: A hallmark feature of Haab's striae is their orientation. They are typically positioned horizontally or concentric to the limbus (the border between the cornea and the sclera).
- Distinguishing from Birth Trauma Tears: It's vital for clinicians to differentiate Haab's striae from other types of Descemet's tears, particularly those resulting from birth trauma. While Haab's striae are horizontal or concentric, Descemet's tears caused by birth trauma are usually vertical or obliquely oriented. This difference in orientation helps determine the etiology of corneal opacities in infants.
Comparison of Corneal Tears:
- Haab's Striae (Primary Congenital Glaucoma):
- Cause: Acute stretching of the cornea due to high intraocular pressure.
- Orientation: Typically horizontal or concentric to the limbus.
- Descemet's Tears (Birth Trauma):
- Cause: Mechanical injury to the cornea during the birthing process.
- Orientation: Usually vertical or obliquely oriented.
Understanding Haab's striae is essential for the early diagnosis and management of primary congenital glaucoma, as prompt intervention can help preserve vision.